(1) Field of the Invention
The present invention relates generally to a device for controlling appliances, such as electric stoves or ranges, and in particular to a device for automatically disconnecting the appliance from the source of electrical current after a preset period of time.
(2) Description of the Prior Art
Electrical heating appliances, especially stoves or ranges, can create a fire hazard if inadvertently left on after use. To address this concern, it has been proposed to include an audible alarm that is activated after a preset time period, alerting the user to the need to turn off the appliance. Such alarms are useless, however, when the user is not within hearing distance.
U.S. Pat. No. 5,289,158 to Neves describes a device for automatically disconnecting power to a range if the range is left on for a predetermined period of time at a predetermined power level. The Neves device is comprised of a sensing box that is electrically connected to a display and control box. The sensing box is designed to be plugged into an electrical receptacle with the range being plugged into the sensing box, while the control box is designed to be attached to a readily accessible part of the range, e.g. by a magnet.
The Neves sensing box includes means for sensing the level of current flowing to the range, a means timing the current flow, and disconnect means for opening the circuit is based upon a combination of current flow and time. The control box includes a signal means to indicate that the current has been disconnected, a reset button to restore power to the range, and an override switch to override the system if more time is required.
U.S. Pat. No. 5,073,701 to Ljunggren also recognizes the potential danger in failing to turn off ranges and other cooking appliances for an extended period of time. Ljunggren addresses this concern by using a detector to detect movement of a knob used to set the desired power level of a range. The detector is connected to a time counting arrangement or timer which, upon activation, counts up to a predetermined time. At the end of the predetermined time, a signal is generated to inactivate the electrical circuit. Touching of the knob during use automatically resets the timer.
Devices of the above types are useful in automatically turning off a range after a predetermined period of time, and thus minimizing the fire hazard. However, the period of time at which the range operates is not readily controllable by the operator. Also, there is no provision made for controlling the timing in a simple to operate manner that is easily performed by the elderly or physically handicapped. A device addressing these deficiencies in the prior art would result in considerable improvements in safety and convenience.